The Lemon Drop Iris, like the Orange Drop Iris, is an evergreen perennial that may get two to three feet tall at maturity. The big difference between Lemon and Orange Drop is the coloring on the petals. Lemon Drop has yellow spots near the base of the flower while Orange Drop has orange spots. They both have narrow, dark green leaves. Both plants are often found along the margins of ponds in their native South African home.They are both hybrids of the Dietes iridioides and the Dietes bicolor.